A study was carried out into the computational fluid dynamic simulation of bio-oil combustion. Measurements were taken in an empirical burner to obtain information regarding the flow behaviour. A surrogate fuel was developed to mimic the unique chemical and physical properties of bio-oil combustion. The resulting computational model of the burner domain and surrogate fuel was compared with empirical data. The bio-oil model displayed a good agreement with the data in terms of the combustion behaviour, but was limited by the uncertain flow solution associated with the burner used.

Biomass fast pyrolysis liquid, also known as bio-oil, is a promising renewable fuel for heat and power generation; however, implementing crude bio-oil in some current combustion systems can degrade combustion performance and emissions. In this study, optimizing fuel properties to improve combustion is considered. Various bio-oils with different fuel properties are tested in a pilot stabilized spray burner under very close flow conditions. Effects of solids, ash and water content of bio-oil as well as ethanol blending were examined. The results show the amount of solids and ash fractions of the fuel were correlated with combustion efficiency. The CO and unburned hydrocarbon emissions decreased with both water and ethanol content. Increasing the fuel’s volatile content by blending in ethanol has been shown to improve flame stability. Also, the organic fraction of particulate matter emissions was found to be a strong function of the thermogravimetric analysis residue of the fuel.

Fast pyrolysis, the rapid thermal decomposition of organic material in the absence of oxygen, is a process that can be used to convert biomass into liquid fuels and chemicals. When performed at the micro-scale, pyrolysis is useful for characterizing biomass structure, as well as determining the pyrolysis products that can be generated from specific biomass feedstocks. Indeed, microscale pyrolysis coupled with on-line analysis of the pyrolysis vapors by GC/MS, so-called pyrolysis-GC/MS (Py-GC/MS), is a technique that can be used to characterize the structure and composition of the various components of lignocellulosic and microalgal biomass based on their pyrolysate distributions. Pyrolysates produced also provide insight into the range of products that can be expected when biomass feedstocks are subjected to thermal decomposition processes. This dissertation focuses on the Py-GC/MS analysis of lignocellulosic biomass such as sorghum and Scenedesmus sp. microalgae, in addition to high-lignin feedstocks such as walnut shells, coconut shells, olive pits and peach pits. The differences in the pyrolysate distributions among these biomass types are correlated with differences in the structure and composition of the biopolymers, mainly cellulose, hemicellulose and lignin, present in the biomass. Py-GC/MS analysis of lignin extracted from endocarp feedstocks is also emphasized. In addition to biomass and extracted lignin, sinapyl (S) and coniferyl (G) alcohol have been analyzed by Py-GC/MS in order to understand the relationship between the corresponding pyrolysates and sinapyl/coniferyl ratios of lignin present in lignocellulosic biomass.

The significant generation of municipal solid waste (MSW) has become a controversial global issue. Pyrolysis and gasification technologies for treating rejects from solid waste disposal sites (SWDSs), for which over 50 % of MSW is attributed to combustible species, have attracted considerable attention. MSW is an alternative energy source that can partly replace fossil resources; there is an increasing awareness that global warming caused by the utilization of fossil resources is occurring. The goal of this thesis is to realize the efficient and rational utilization of MSW and decrease the harmful impact of pollutants, such as dioxin, HCl, and CO2, on the environment. To achieve this goal, some fundamental studies have been experimentally and numerically conducted to enhance the understanding of the properties of municipal solid waste thermal conversion. In this thesis, the pyrolysis behaviors of single pelletized recovered fuel were tested. A detailed comparison of the pyrolysis behaviors of typical recovered solid waste and biomass particles was conducted. A swelling phenomenon with a swelling ratio of approximately 1.6 was observed on the surface of pelletized recovered fuels. Subsequently, a particle model was constructed to describe the thermal conversion process for large recovered fuel particles that are composed of a high fraction of polyethylene (PE) and a comparable low fraction of cardboard. The results indicate that an understanding of the heat transfer mechanism in highly porous and molten structures and the selection of a heat transfer model are crucial for accurate prediction of the conversion process. MSW pyrolysis is a promising method for producing liquid products. With the exception of lignocellulosic materials, such as printing paper and cardboard, PE, polystyrene (PS), polypropylene (PP), polyethylene terephthalate (PET), and polyvinyl chloride (PVC) are the six main polymers in domestic waste in Europe. Characterization studies of the products obtained from these individual components, such as PE, PET, PVC, printing paper, and cardboard, have been conducted on a pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) system and a fixed-bed reactor. The possible pathways for the formation of the main primary/secondary products in rapid and conventional pyrolysis were also discussed. MSW steam gasification with CaO was performed in a batch-type fixed-bed gasifier to examine the effect of CaO addition on the heat transfer properties, pollutant removal, and devolatilization and char gasification behaviors in the presence of steam. A new carbon capture and recycle (CCR) system combined with an integrated municipal solid waste system was proposed. The foundation of the system is the development of a novel method to remediate CO2 using a high-temperature process of reforming CH4 and/or O2 and/or H2O without catalysts. Thermodynamic and experimental studies were performed. High temperatures significantly promoted the multi-reforming process while preventing the problem of catalyst deactivation. Potential improvements in the efficiency of the novel technology can be achieved by optimizing the reforming reactants. Landfill gas (LFG) and fuel gas from bio-waste treatment contain a considerable fraction of CH4, which may be a source of CH4 for this process. / <p>QC20141028</p>

In the first part of this work, the structural and thermal characteristics of polyacrylonitrile, polyacrylonitrile films treated under the electrolysis conditions in the absence of thiophene, polythiophene and the mechanical mixture and a conducting copolymer of polyacrylonitrile/polythiophene have been studied by pyrolysis mass spectrometry technique. The thermal degradation of polyacrylonitrile occurs in three steps / evolution of HCN, monomer, low molecular weight oligomers due to random chain cleavages are followed by cyclization and dehydrogenation reactions yielding crosslinked and unsaturated segments. Pyrolysis of the treated polyacrylonitrile films indicated decrease in the yields of monomer and oligomers, and increase in the amount of products stabilized by cyclization reactions were detected. Polythiophene degrades in two steps / the loss of the dopant and degradation of polymer backbone. The evolution profiles of polythiophene based products from polythiophene/polyacrylonitrile showed nearly identical trends with those recorded during the pyrolysis of pure polythiophene. However, evolution of HCN and the degradation products due to the homolytic cleavages of the polymer backbone continued through out the pyrolysis indicating a significant increase in their production. Furthermore, the yield of thermal degradation products associated with decomposition of the unsaturated cyclic imine segments decreased. A careful analysis of the data pointed out presence of mixed dimers confirming copolymer formation. In the second part of this work, a poly(acrylonitrile-co-butadiene) sample involving monomer units having quite similar molecular weights have been analyzed to investigate the limits of the pyrolysis mass spectrometry technique. Pyrolysis of aged poly(acrylonitrile-co-butadiene) indicated oxidative degradation of the sample. Keywords: conducting copolymer, polyacrylonitrile, polythiophene, polybutadiene, direct pyrolysis mass spectrometry

ABSTRACT CHARACTERIZATION OF CONDUCTING POLYMERS OF ESTER LINKAGE CONTAINING THIOPHENE DERIVATIVES VIA MASS SPECTROSCOPY Aslan, Evren M.Sc., Department of Chemistry Supervisor: Prof. Dr. Levent Toppare Co-Supervisor: Prof.Dr. Jale Hacaloglu December 2004, 86 pages In order to investigate the thermal and structural characteristics of terepthalic acid bis-(2-thiophen-3-yl-ethyl)ester (TATE), decanedioic acid bis-(2-thiophen-3-yl- ethyl) ester (DATE) and octanoic acid 2-thiophen-3-yl-ethyl ester (OTE), their corresponding homopolymers, copolymers with thiophene and polythiophene, pyrolysis mass spectrometry technique was utilized. The results were discussed in detail considering the effects of spacer group in between ester linkages. Thermal Gravimetry Analysis was used to investigate the weight loss for polymers and monomers. Conductivities of samples were measured by four-probe technique. It was found that when the ester linkages contain hydrocarbon chains, the growth of polymer occurred through both 2 and 5 positions. On the other hand, when the ester linkages contain more rigid groups such as phenyl, steric hindrance inhibited the growth of the polymer through 2- position and polymerization proceeded via coupling of thiophene moieties mainly at 5-position yielding a polymer with lower conductivity. Though the structure of P(OTE) is inherently different than P(DATE) and P(TATE) extent of network structure is also quite low for this polymer compared to PTh. Similar thermal characterizations were recorded indicating that thermal units were not significantly affected by the presence of TATE, DATE or OTE for all copolymer samples.

In the first part of this study, the structtural and thermal characterization of electrochemically and chemically polymerized poly(paraphenylene vinylene), (PPV), have been investigated by direct pyrolysis mass spectrometry. Thermal characteristics, and degradation products of electrochemically prepared poly(paraphenylene vinylene). Pyrolysis study indicated that thermal decomposition of PPV occurs at least two steps. The first being due to the loss of supporting electrolyte present and the second being decomposition of the polymer backbone.In the second part of the study, direct insertion probe pyrolysis mass spectrometry (DIP-MS) technique was used to perform the thermal and the structural characterization of electrochemically synthesized polyaniline,PANI. The effect of dopant used (HCL, HNO3 and H2SO4) and synthesis period have been investigated. For all the samples studied, three main thermall degradation stages have been recorded / evolution of low molecular weight species, evolution of dopant based products and evolution of degradation products of polymer.

Lignin, a byproduct of the chemical pulping can be gasified to produce fuel gas and value-added products. Two lignins, MeadWestvaco (MWV) lignin and Sigma Aldrich (SA) lignin, were studied using two different reactors. A laminar entrained flow reactor (LEFR) was used initially to determine the effect of lignin type, temperature and residence time on char yield and fixed carbon conversion during pyrolysis and gasification. During both pyrolysis and gasification, the maximum decrease in char yield took place in the initial stage of the reaction and there was little change at longer residence times. There was not much difference between pyrolysis and gasification in the residence times obtained in the LEFR. Furthermore, a thermogravimetric analyzer (TGA) was used to study the effect of lignin type on pyrolysis and gasification. The reaction rates and char yields were affected by the lignin composition. Lignin pyrolysis showed similar behavior until 600°C but only the high-ash SA lignin showed secondary pyrolysis reactions above 600°C. Carbon gasification reactions were delayed in SA lignin. Na2CO3 addition made the primary pyrolysis reaction occur at a lower rate and enhanced the rate for secondary pyrolysis reactions. Fourier Transform Infrared (FTIR) Spectroscopy results showed that the significant loss of spectral detail started at different temperatures for MWV lignin and SA lignin. Kinetic parameters obtained using differential and Coats - Redfern integral method were comparable at lower temperatures but varied at high temperatures. Na2CO3 addition decreased the activation energy of primary pyrolysis.

Thesis (PhD.(Metallurgy)--University of Pretoria, 2008. / Includes bibliographical references.

Mémoire (Sc. A.)--Université du Québec à Chicoutimi, 1987. / Bibliogr: ff. 114-118. Document électronique également accessible en format PDF. CaQCU